topic Array in SAS Programming

Array

uabcms — Mon, 23 Apr 2012 16:00:55 GMT

Patient ID	Admit date	Discharge Date	status
1	28jan11	01feb11	keep
1	16feb11	26feb11	delete
1	12mar11	22mar11	keep
1	27mar11	01apr11	delete
1	12apr11	13apr11	delete
1	22may11	24may11	keep
1	06jun11	09jun11	delete

I am trying to create a file of 'index' records only. Index being defined as 'the beginning of a new 30-day window.

The table above has multiple admits for a single patient. I added the 'Status' column for this discussion.

It doesn't exist in the data but represents the result I would like to get. I am comparing admits dates with

previous discharge dates.

The 2nd obs is within 30 days of the 1st obs so I want to get rid of the 2nd record. The 3rd obs is >30 days from

the 1st obs so I want to keep that record as a new index record. The 4th and 5th obs are both within 30 days of

the new index so I want to get rid of those. The 6th is a new index case and the 7th needs to be deleted.

I think this can probably be done in an array but not sure how to construct it.

Thanks

Re: Array

Haikuo — Mon, 23 Apr 2012 16:12:40 GMT

I am sure there will be slicker approaches, but for now, you could try this:

data have;

input PatientID$ (Admitdate DischargeDate) (:date9.) status$;

format Admitdate DischargeDate date9.;

cards;

1 28jan11 01feb11 keep

1 16feb11 26feb11 delete

1 12mar11 22mar11 keep

1 27mar11 01apr11 delete

1 12apr11 13apr11 delete

1 22may11 24may11 keep

1 06jun11 09jun11 delete

;

data want (drop=_:);

retain _date;

set have;

by patientid;

if first.patientid then _date=dischargedate;

if 0<= admitdate-_date < 30 then delete;

else _date=dischargedate;

run;

proc print;run;

Haikuo

Update: if you want to get a little bit fancier and avoid using 'retain', here is an array approach:

data want ;

array d(1) _temporary_;

set have;

by patientid;

if first.patientid then d(1)=dischargedate;

if 0<= admitdate-d(1) < 30 then delete;

else d(1)=dischargedate;

run;

Re: Array

uabcms — Mon, 23 Apr 2012 19:40:07 GMT

I found that the above code did not work in a case such as below.

Admit 07OCT10	Discharge 07OCT10
07OCT10	11OCT10
11OCT10	23NOV10

Admit

07OCT10

Discharge

07OCT10

11OCT10

23NOV10

The above data are for a single patient ID. It looks like cases where the admit

date is the same as the previous discharge date are being excluded . Any suggestions?

Re: Array

PGStats — Mon, 23 Apr 2012 21:10:51 GMT

This will work:

data have;
input PatientID$ (Admitdate DischargeDate) (:date9.) status$;
format Admitdate DischargeDate date9.;
cards;
1 28jan11 01feb11 keep
1 16feb11 26feb11 delete
1 12mar11 22mar11 keep
1 27mar11 01apr11 delete
1 12apr11 13apr11 delete
1 22may11 24may11 keep
1 06jun11 09jun11 delete
1 07oct11 07oct11 keep
1 07oct11 11oct11 delete
1 11oct11 23oct11 delete
;

proc sql nowarnrecurs;
delete from have as B
where exists(select * from have as A where A.patientId=B.patientId and
intck("DAY", A.DischargeDate, B.AdmitDate, "CONTINUOUS") between 0 and 30);

quit;

Re: Array

Haikuo — Tue, 24 Apr 2012 02:38:04 GMT

This will fix that.

data have;

input PatientID$ (Admitdate DischargeDate) (:date9.) status$;

format Admitdate DischargeDate date9.;

cards;

1 07OCT10 07OCT10 keep

1 07OCT10 11OCT10 delete

1 1OCT10 23NOV10 delete

1 28jan11 01feb11 keep

1 16feb11 26feb11 delete

1 12mar11 22mar11 keep

1 27mar11 01apr11 delete

1 12apr11 13apr11 delete

1 22may11 24may11 keep

1 06jun11 09jun11 delete

;

data want (drop=_:);

retain _date;

set have;

by patientid;

if (first.patientid or not (admitdate-_date < 30)) then _date=dischargedate;

else delete;

run;

Good Luck,

Haikuo

Re: Array

FloydNevseta — Tue, 24 Apr 2012 12:53:30 GMT

data want (drop=_:);

retain _lastdischdt;

set have;

by patientid;

if not ( first.patientid or (admitdate-_lastdischdt >= 30) ) then delete;

_lastdischdt = dischargedate;

run;